According to Moscow-based cybersecurity firm Kaspersky Lab on Tuesday, various versions of Ztorg have targeted Android smartphone owners in the past.

"This isn’t the first time cybercriminals distributed Ztorg modules through Google Play," the company said. "In April, they uploaded a module that can click on Google Play Store app buttons to install or even buy promoted apps."

In May, researchers discovered that Ztorg-infected app Privacy Lock had been downloaded more than one million times. Additionally, an infected Pokémon Go guide was downloaded more than 500,000 times in September of last year. Both were removed from the Google Play Store.

Malware targeting Android users is on the rise - the operating system is "more open and adaptable," which makes it easier to hack.

Infected apps are becoming problematic for Android application developers and consumers. As of last spring, an estimated 1.3 to 1.4 billion people owned Android smartphones.

Users should avoid downloading and installing apps from unknown sources, even if they're featured in the Google Play Store. Reading user reviews can be helpful - apps that display suspicious behavior will often have low ratings.

Keeping mobile devices updated and installing security apps is also recommended to protect against unwanted infections.